Manx Utilities Reservoir Hydrographic Survey, July 2019

Asset owners responsible for managing water resource require a detailed understanding the depth and morphology of reservoirs to understand the volumes of raw water available to treatment works and nowhere is this more important than the Isle of Man where utility engineers have limited options available to overcome water shortages caused under circumstances such as prolonged drought. Manx Utilities instructed HydroSurv to carry out bathymetric surveys and sediment profiling for all their operational reservoirs on the Isle of Man, enabling water resource specialists to gain an up to date understanding of the size, shape and volume of the reservoirs and the extent of sediment accumulation since construction.
In partnership with MarynSol – a consultancy firm with specializing in advanced data acquisition, management and analytics from unmanned platforms, HydroSurv mobilized a micro Unmanned Surface Vessel (USV) installed with a sonar array consisting of dual profiling heads and a sub-bottom profiler, sufficiently small and lightweight to be readily transferred between worksites using a small vehicle and a three-man survey team. Live profiling data was streamed from a modular survey payload using the host USV’s communication system, enabling surveyors to monitor the integrity of survey data acquisition from the reservoir bank, making adaptions to the mission plan in real-time where necessary to provide adequate data density. This approach resulted in excellent on-water productivity; during a five-day mobilized period, the survey team surveyed five reservoirs (a collective area greater than 51 hectares); simultaneously gathering bathymetry and sediment analysis data. The use of an unmanned vessel eliminated any need for surveyors to work afloat, minimizing safety risks as well as nuisance or disturbance caused by small boats or outboard motors. Water Resource Specialists at Manx Utilities will draw upon the high-accuracy survey data to inform strategic planning, assuring consumers of sustainable and reliable water supply now and in the future.